The present invention relates to a new and improved construction of a double-flank composite error tester for determining gear errors.
In its more particular aspects the present invention specifically relates to a new and improved double-flank composite error tester for determining gear errors and which comprises at least two gear holding supports. At least one of the at least two gear holding supports is mounted at a spring-loaded displaceable slide which can be displaced relative to another gear holding support of said at least two gear holding supports. In such double-flank composite error tester, prior to engaging the teeth of at least one pair of gears, the tooth tip of one gear of the pair of gears can be aligned with a tooth space of the other gear of the pair of gears.
A double-flank composite error tester for determining gear errors as known, for example, from the MAAG Company brochure "DAS-2", A53a-D 8.78, serves for rapidly determining the total effect of all gear errors present in external or internal spur or helical gears as well as in bevel gears and worm gears by rolling two of such gears in mesh with zero backlash. This known double-flank composite error tester comprises a bed made of gray cast iron. On guideways of the bed there are mounted a fixedly clampable or adjustable slide and a displaceable or floating, spring-loaded slide. These two slides carry the two gear holding supports for the gears to be tested. There is further mounted a dial indicator at the displaceable slide.
The two gears to be tested are manually placed in such a relative position that the tooth tip of one of the gears and the tooth space or gap of the other one of the gears face each other and are arranged on a line which interconnects the central axes of the two gear holding supports. The two gears are meshed or interengaged with zero backlash by displacing the fixedly clampable or adjustable slide in such a manner that the working gear center distance of the two gears is precisely adjusted and the fixedly clampable or adjustable slide is then fixedly clamped. The displaceable or floating slide which carries the dial indicator is supported at balls and is held in its end position by means of the spring load.
Whenever the interengaged pair of gears is rotated either manually or by suitable drive means, the displaceable or floating slide transmits its movements to the dial indicator or a recording device by means of which the total effects of all gear errors can be recorded. The diagrams which are obtained in the last case can then be evaluated with respect to different aspects: Radial run-out errors are variations in the gear center distance during rotation of the gears; pitch errors are recognizable in the diagram by acute, irregularly occurring fluctuations or excursions which vary from tooth to tooth; profile form errors are deviations from the true involute referred to the relevant base circle and result in a diagram of wave-like appearance; pressure angle errors occur when the flank profile is incorrectly positioned relative to the base circle and are recognizable in the diagram by regularly occurring fluctuations or excursions.
In the known double-flank composite error tester, as explained hereinbefore, the gear teeth of the two gears must be manually aligned relative to each other prior to interengagement such that a tooth faces a tooth space and a collision is prevented between the tooth tip of one gear and the tooth tip of the other gear. Such manual alignment operation is too expensive with respect to time for a measuring operation integrated in a production line. Therefore, the known double-flank composite error tester can not be used in such cases.